Compressor protection and diagnostic system

ABSTRACT

A compressor assembly includes a shell, a compressor housed within the shell, and a motor drivingly connected to the compressor. In addition, a sensor assembly is provided for monitoring operating parameters of the compressor assembly. Processing circuitry, in communication with the sensor assembly, is operable to process the operating parameters of the compressor assembly according to predefined rules. Furthermore, a terminal assembly is hermetically secured to the shell and is in communication with the sensor assembly. A plug is attached to the terminal assembly outside of the shell and serves to operably connect the processing circuitry with the sensor assembly.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of U.S. Provisional Application No.60/533,236, filed on Dec. 30, 2003. The disclosure of the aboveapplication is incorporated herein by reference.

FIELD

The present teachings relate to compressors, and more particularly, toan improved diagnostic system for use with a compressor.

BACKGROUND

Compressors are used in a wide variety of industrial and residentialapplications. More particularly, compressors are often used to circulaterefrigerant within a refrigeration or heat pump system to provide adesired heating or cooling effect. In addition, compressors are alsoused to inflate or otherwise impart a fluid force on an external objectsuch as a tire, sprinkler system, or pneumatic tool. In any of theforegoing applications, it is desirable that a compressor provideconsistent and efficient operation to ensure that the particularapplication (i.e., refrigeration system or pneumatic tool) functionsproperly. To that end, alerting when a compressor has failed or is inneed of repair helps prevent unnecessary compressor damage and systemfailures.

Compressors are intended to run trouble free for the life of thecompressor and provide a consistent supply of compressed fluid. Whilecompressors are increasingly reliable, monitoring operation of thecompressor allows one to discontinue its operation should an error orfault arise. Discontinuing use of the scroll compressor underunfavorable conditions will likely prevent damage to the compressor.

Faults causing a compressor to shut down may be electrical or mechanicalin nature. Electrical faults generally have a direct effect on theelectric motor in the compressor, and may destroy the electric motor orits associated components. Mechanical faults may include faulty bearingsor broken parts, and typically raise the internal temperature of therespective components to very high levels, sometimes causing malfunctionof and damage to the compressor. In addition to mechanical andelectrical faults, “system” faults may occur, such as those resultingfrom an adverse level of refrigerant or lubricant or to a blocked flowcondition. Such system faults may raise the internal compressortemperature or pressure to high levels, which may damage the compressor.

SUMMARY

A compressor assembly generally includes a shell, a compressor housedwithin the shell, and a motor drivingly connected to the compressor. Asensor assembly is provided for monitoring operating parameters of thecompressor assembly, including the temperature of an electricalconductor supplying current to the motor. Processing circuitry incommunication with the sensor assembly processes the operatingparameters of the compressor. A terminal assembly is hermeticallysecured to the shell and is in communication with the sensor assembly,while a connector is attached to the terminal assembly outside of theshell and serves to operably connect the processing circuitry with thesensor assembly.

BRIEF DESCRIPTION OF THE DRAWINGS

The present teachings will become more fully understood from thedetailed description and the accompanying drawings, wherein:

FIG. 1 is a perspective view of a compressor incorporating a firstprotection system in accordance with the teachings;

FIG. 2 is a cross-sectional view of the compressor of FIG. 1;

FIG. 3 is a more detailed sectional view of the protection system ofFIG. 2;

FIG. 4 is a perspective view of the protection system of FIG. 2;

FIG. 5 is a schematic representation of the protection system of FIG. 2;

FIG. 6 is an alternate schematic representation of the protection systemof FIG. 2;

FIG. 7 is a perspective view of a compressor incorporating a secondprotection system in accordance with the teachings;

FIG. 8 is a cross-sectional view of the compressor of FIG. 7;

FIG. 9 is a more detailed sectional view of the protection system ofFIG. 7;

FIG. 10 is a perspective view of the protection system of FIG. 7;

FIG. 11 is a schematic representation of the protection system of FIG.7;

FIG. 12 is a perspective view of a compressor incorporating a thirdprotection system in accordance with the teachings;

FIG. 13 is a perspective view of a cluster block of the protectionsystem of FIG. 12;

FIG. 14 is a perspective view of the cluster block of FIG. 13incorporated into a current-sensor assembly;

FIG. 15 is a front view of the cluster block and current-sensor assemblyof FIG. 14 incorporated into a housing;

FIG. 16 is a front view of the cluster block and current-sensor assemblyof FIG. 14 incorporated into a housing and mounted to the compressor ofFIG. 12;

FIG. 17 is a flow-chart depicting operation of a compressor inaccordance with the teachings;

FIG. 18 is a flow-chart depicting operation of a compressor between arun condition and a shutdown condition in accordance with the teachings;

FIG. 19 is a perspective view of a compressor incorporating a fourthprotection system in accordance with the teachings;

FIG. 20 is a cross-sectional view of the compressor of FIG. 19;

FIG. 21 is a perspective view of the protection system of FIG. 19;

FIG. 22 is a perspective view of the protection system of FIG. 20showing a current-sensing arrangement; and

FIG. 23 is a schematic representation of a compressor network inaccordance with the teachings.

DETAILED DESCRIPTION

The following description is merely exemplary in nature and is in no wayintended to limit the teachings, its application, or uses.

With reference to the figures, a scroll compressor 10 is provided andincludes a compressor protection and control system 12. The protectionand control system 12 is operable to selectively shut down thecompressor 10 in response to sensed compressor parameters in an effortto protect the compressor 10 and prevent operation thereof whenconditions are unfavorable. While a scroll compressor 10 will bedescribed herein, it should be understood that any compressor could beused with the protection and control system 12 of the present invention.

With particular reference to FIGS. 1 and 2, the compressor 10 is shownto include a generally cylindrical hermetic shell 14 having a welded cap16 at a top portion and a base 18 having a plurality of feet 20 weldedat a bottom portion. The cap 16 and base 18 are fitted to the shell 14such that an interior volume 22 of the compressor 10 is defined. The cap16 is provided with a discharge fitting 24, while the shell 14 issimilarly provided with an inlet fitting 26, disposed generally betweenthe cap 16 and base 14, as best shown in FIGS. 2 and 8. In addition, anelectrical enclosure 28 is fixedly attached to the shell 14 generallybetween the cap 16 and base 18 and operably supports a portion of theprotection system 12 therein, as will be discussed further below.

A crankshaft 30 is rotatively driven by an electric motor 32 relative tothe shell 14. The motor 32 includes a stator 34 fixedly supported by thehermetic shell 14, windings 36 passing therethrough, and a rotor 38press fitted on the crankshaft 30. The motor 32 and associated stator34, windings 36, and rotor 38 are operable to drive the crankshaft 30relative to the shell 14 to thereby compress a fluid.

The compressor 10 further includes an orbiting scroll member 40 having aspiral vane or wrap 42 on the upper surface thereof for use in receivingand compressing a fluid. An Oldham coupling 44 is positioned betweenorbiting scroll member 40 and a bearing housing 46 and is keyed toorbiting scroll member 40 and a non-orbiting scroll member 48. TheOldham coupling 44 is operable to transmit rotational forces from thecrankshaft 30 to the orbiting scroll member 40 to thereby compress afluid disposed between the orbiting scroll member 40 and non-orbitingscroll member 48. Oldham coupling 44 and its interaction with orbitingscroll member 40 and non-orbiting scroll member 48 is preferably of thetype disclosed in assignee's commonly-owned U.S. Pat. No. 5,320,506, thedisclosure of which is incorporated herein by reference.

Non-orbiting scroll member 48 also includes a wrap 50 positioned inmeshing engagement with wrap 42 of orbiting scroll member 40.Non-orbiting scroll member 48 has a centrally disposed discharge passage52 which communicates with an upwardly open recess 54. Recess 54 is influid communication with discharge fitting 24 defined by cap 16 andpartition 56, such that compressed fluid exits the shell 14 via passage52, recess 54, and fitting 24. Non-orbiting scroll member 48 is designedto be mounted to bearing housing 46 in a suitable manner such asdisclosed in the aforementioned U.S. Pat. No. 4,877,382 or U.S. Pat. No.5,102,316, the disclosures of which are incorporated herein byreference.

Referring now to FIG. 2, electrical enclosure 28 includes a lowerhousing 58, an upper housing 60, and a cavity 62. The lower housing 58is mounted to the shell 14 using a plurality of studs 64 which arewelded or otherwise fixedly attached to the shell 14. The upper housing60 is matingly received by the lower housing 58 and defines the cavity62 therebetween. The cavity 62 is operable to house respectivecomponents of the compressor protection and control system 12, as willbe discussed further below.

With particular reference to FIGS. 1-6, the compressor protection andcontrol system 12 is shown to include a sensor system 66, processingcircuitry 68, and a power interruption system 70. The sensor system 66,processing circuitry 68, and power interruption system 70 cooperate todetect and correct fault conditions in an effort to prevent damage tothe compressor 10 and to alert a user to the fault condition (i.e., vialight emitting devices (LED) and the like). The compressor protectionand control system 12 detects and responds to run winding delay, motoroverload, missing phase, reverse phase, motor winding current imbalance,open circuit, low voltage, locked rotor currents, excessive motorwinding temperature, high discharge temperature conditions, low oilpressure, lack of three phase power, open thermistors, welded or opencontactors, and short cycling. For example, a compressor protection andcontrol system 12 for a particular type and size compressor may be assummarized in Table 1, but other compressor types and sizes may havedifferent thresholds, parameters, indicators and limits. TABLE 1 ALARMOCCURRENCE ACTION LED LOCKOUT RESET Run Excessive delay in Trip (openRed flashes 10 Trips Normal run winding Winding energizing one contactorrelay), one time In a Row operation OR Cycle Delay winding after a firstwait 5 minutes, between pauses power winding is energized then closecontactor relay Missing One phase is missing Trip (open Red flashes 10Trips All three phases Phase contactor relay), two times In a Rowpresent OR Cycle wait 5 minutes, between pauses power then closecontactor relay Reverse Three phase power Trip (open Red flashes 4 TripsPhase orientation Phase leads are connected contactor relay), threetimes In a Row correct OR Cycle improperly causing wait 5 minutes,between pauses power motor to run then close backwards contactor relayWelded Contactor is None Red flashes None N/A Contactor providing threefour times phase power to between pauses compressor when contactorshould be open Low Voltage Supply voltage to Trip (open Red flashes NoneSupply voltage AMPS is below the contactor relay), five times remains inalarm threshold wait 5 minutes between pauses “normal” range No ThreeCurrent is not None Red flashes None Three phase current Phase detectedat five times is detected when Power compressor between pauses demand ispresent terminals when OR demand is not demand is present present and nocurrent is detected Low Oil Oil pressure is too Trip (open Red flashesNone Oil pressure Pressure low for an extended contactor relay), onetime sensor alarm period of time close contactor between pauses relay isopen relay when oil relay closes Discharge Discharge temperature Trip(open Red flashes 4 Trips Discharge temps Temperature is too highcontactor relay), two times In 3 Hours remain in “normal” wait 30minutes, between pauses range OR Cycle then close power contactor relayMotor Motor temperature Trip (open Red flashes 4 Trips Motor tempsremain Temperature is too high OR contactor relay), three times In 3Hours in “normal” range motor temperature wait 30 minutes, betweenpauses OR Cycle power sensor is short then close circuited contactorrelay Locked Current to Trip (open Red flashes 4 Trips Current to Rotorcompressor exceeds contactor relay), four times In a Row compressorremains 300 Amps or fails wait 5 minutes, between pauses in “normal”range to decrease from then close OR Cycle power initial lockedcontactor relay rotor current level or exceeds 300 Amps or 40% of peaklocked rotor Amps (LRA) while running Motor Current to Trip (open Redflashes None Current to Overload compressor contactor relay), five timescompressor remains exceeds maximum wait 5 minutes, between pauses in“normal” range continuous current then close (MCC) rating contactorrelay Open One or more Trip (open Red flashes None Discharge tempsThermistor discharge/motor contactor relay), six times remain in“normal” temperature wait 30 minutes, between pauses range OR Cyclepower sensors are then close disconnected contactor relay

As shown above in Table 1, a run winding delay is generally defined asan excessive delay in energizing one winding after a first winding isenergized. When a start winding has been energized, a run winding mustbe energized within two seconds. If the run winding is not energizedwithin this time period, the system 12 shuts down the compressor motor32. If the run winding is energized first, the start winding must beenergized within two seconds. If the start winding is not energizedwithin this time period, the system 12 similarly shuts down the motor32. For a plural compressor 10 c (FIG. 19) the system 12 senses both thestart and run winding current at start up. When the compressor 10 c isin the running state, if either the start or run winding completely dropout for more than two seconds, the system 12 shuts down the motor 32.

A missing phase fault is generally defined when one phase of the motor32 is missing. Once the start winding is energized, the system 12ensures that current is present in all phases within 700 millisecondsafter current is detected in one of the phases. If current is detectedin at least one phase and no current is detected in the other phase(s),then the system 12 shuts down the motor 32. Generally speaking, acurrent imbalance of greater than 50 percent is required before themotor 32 is interrupted. The run winding is monitored and protectedagainst missing phase in a similar fashion. During normal runningoperation (i.e., while demand is present), if a loss of current in anyphase of the motor 32 is detected for a period of one second, the motor32 is shut down.

A reverse phase is generally defined when three phase power leads areconnected improperly, thereby causing the motor 32 to run backwards. Ifthe phase sequence of the three phase power is incorrect, the system 12shuts down the compressor 10. The phase sequence is measured roughly 700milliseconds after the demand signal and current is sensed in the startwinding. It should be noted that the motor 32 may rotate “backwards” fora short period of time after power has been removed from the compressor10 due to pressure equalization. Due to this phenomenon, reverse phaseis only monitored for roughly the first five seconds of each compressorstart cycle.

A welded contactor fault is declared when a contactor supplies threephase power to the compressor 10 when contactor should be open. Thiscondition is detected after the motor 32 has been shut down. If currentpersists after roughly two seconds of shutdown, then it will be assumedthat the contacts have welded or mechanically “jammed” shut.

A motor overload condition is generally referred to a situation wherecurrent to the compressor 10 exceeds a maximum continuous current (MCC)rating. Overload current is defined as current that exceeds 110 percentrated MCC for more than 60 seconds. If the part winding motor current inany leg of either start or run winding exceeds the pre-programmed limit,then the system 12 shuts down the motor 32. The MCC overload detectiondoes not start until five seconds after start up and continues untilshutdown. If a compressor's MCC is not programmed, overload current isdetected by the a motor temperature sensor(s). The system 12 detects amissing compressor MCC parameter when it determines that the MCC valueis set to zero Amps, which is the default setting for the compressor 10.

A locked rotor condition is declared when current to the compressor 10exceeds roughly 300 Amps, fails to decrease from an initial locked rotorcurrent level, exceeds 300 Amps, or is roughly 40 percent of peak lockedrotor Amps (LRA) while running. The locked rotor current during start upis expected to decrease within one second after the motor 32 comes up tospeed and settles down to a normal running current level. The systemmaintains a 100 millisecond buffer of the current readings for the runand start windings. When compressor demand is high, indicating thecompressor has started, the highest peak current in the buffer isrecorded as the locked rotor current. The peak locked rotor current isrecorded as greater than 300 Amps, or as the specific peak value if lessthan 300 Amps.

If the peak locked rotor current in the start winding is greater than300 Amps, a second reading is taken roughly 800 milliseconds after startup (compressor demand is measured high). If the start winding currentvalue is greater than 300 Amps 800 milliseconds after start up, then thesystem 12 assumes that the motor 32 is mechanically seized and thatpower to the motor 32 should be interrupted. If the peak locked rotorcurrent in the start winding is less than 300 Amps, a second reading istaken roughly 800 milliseconds after start up (compressor demand ismeasured high). If the second reading has not dropped to a level lessthan 40 percent of the peak LRA measured, power to the compressor motor32 is interrupted.

For locked rotor conditions that occur after start up has completed, thepeak locked rotor current measured is used. If the peak locked rotorcurrent is greater than 300 Amps, and the running current is measuredabove 300 Amps for 500 milliseconds, power to the motor 32 isinterrupted. If the peak locked rotor current is less than 300 Amps, andthe running current is greater than 40 percent of that peak locked rotorcurrent measured and recorded, power is similarly interrupted. If a peaklocked rotor current of less than 100 Amps is measured, the locked rotordetection is disabled for that compressor run cycle. Such controleliminates nuisance trips if the timing of the start up is disruptedduring troubleshooting of the equipment.

A low voltage fault is declared, and the compressor 12 is shut down, ifthe 220 VAC supply power to the system 12 falls below 170 VAC when acompressor demand signal is present. When the voltage falls to thislevel, the compressor 10 is not allowed to start. Excessive arcing dueto contactor coil chattering during low voltage conditions can lead to awelded contactor and therefore the compressor 10 is shut down under suchcircumstances. The occurrence of low voltage must persist for roughlytwo seconds before an alarm is recorded and power to the motor 32 isinterrupted. The voltage must rise above 180 VAC for a minimum of twoseconds to reset the alarm.

Discharge temperature is monitored to ensure that the dischargetemperature is not above a predetermined threshold value in an effort toprotect the motor 32 and associated scrolls 40, 48. The system 12monitors the discharge temperature in at least two locations and, if aresistance value is greater than roughly 1.33 kΩ+/−5 percent, power tothe motor 32 is interrupted. Power remains interrupted until theresistance falls below roughly 600 Ω+/−5 percent and a thirty (30)minute delay has been completed.

The temperature of the motor 32 is monitored by using at least onepositive-temperature-coefficient (PTC) device ornegative-temperature-coefficient (NTC) device, which may be athermistor-type sensor. If a PTC resistance value is greater thanroughly 4.5 kΩ+/−5 percent, power to the motor 32 is interrupted andremains as such until the PTC resistance falls below roughly 2.75 kΩ+/−5percent and a thirty (30) minute delay has been completed. A shortedthermistor input is read as a low resistance value and indicates therespective motor temperature sensor is jumpered or a board component hasfailed. Any PTC resistance below roughly 100 ohms is interpreted as ashorted thermistor.

An open thermistor fault is declared, and power to the motor 32interrupted, if any thermistor input is read as open circuit. An opencircuit is defined for NTC and PTC thermistors as a resistance higherthan roughly 100 kΩ. The resistance must be read at this level for 60seconds while the compressor 10 is running.

If a compressor demand input is read high for two seconds, and nocurrent is read in any of the current transformer inputs, a no threephase power alarm is declared. Whenever current is detected in anycurrent transformer input or if the demand inputs are read low for twoseconds, the alarm is reset.

In addition to detecting and reporting the above-described faultconditions (Table 1), the system 12 also detects and monitors “warningconditions.” The warning conditions are not as sever as the faultconditions, and therefore do not cause protective action (i.e.,interruption of power to the motor 32), but the warning conditions aremonitored nonetheless and are used a diagnostics and in prevention offault conditions. The warning conditions include a high ambienttemperature warning, a motor overload warning, a locked rotor warning, alow supply voltage warning, a high supply voltage warning, a highdischarge temperature warning, a discharge temperature sensor shortcircuit warning, a high motor temperature warning, a no configurationwarning, and a contactor life warning, each of which is brieflydescribed below.

A high ambient temperature warning is detected when an ambienttemperature sensor measures a temperature above roughly 60 degreesCelsius for more than 60 seconds continuously. The high ambienttemperature warning is reset when the ambient temperature sensormeasures below 60 degrees Celsius for more than 60 seconds continuously.

A motor overload warning is detected when the motor current is at 100percent MCC current level for more than 60 seconds. The motor overloadwarning is reset when the motor current level has dropped below 100percent MCC current level for more than 60 seconds or when a motoroverload alarm becomes active.

A locked rotor warning is detected when a locked rotor event isdetected. Unlike the alarm, which requires multiple events, the warningis detected with a single event. The locked rotor warning is reset whenthe compressor 10 has run five minutes continuously without a lockedrotor event, or when a locked rotor alarm becomes active.

A low supply voltage warning is detected when the supply voltage isbelow 180 VAC for two seconds. A low supply voltage warning is resetwhen the supply voltage is above 190 VAC for two seconds or when a LowSupply Voltage Alarm becomes active.

A high supply voltage warning is detected when the supply voltage isabove 250 VAC for two seconds. A high supply voltage warning is resetwhen the supply voltage is above 240 VAC for two seconds.

A high discharge temperature warning is detected when the dischargetemperature is less than 10 degrees Celsius below the alarm set pointfor each sensor for two seconds. A high discharge temperature warning isreset when the discharge temperature is greater than 15 degrees Celsiusbelow the alarm set point for each sensor for two seconds, or a highdischarge temperature alarm becomes active.

A discharge temperature sensor short circuit warning is detected whenthe resistance measured at the discharge temperature sensors is lessthan 100 Ω for two seconds. A discharge temperature sensor short circuitwarning is reset when the resistance measured is greater than 1 kΩ fortwo seconds.

A high motor temperature warning is detected when a motor temperature isless than 10 degrees Celsius below the alarm set point for two seconds.

A high motor temperature warning will be reset when a motor temperatureis greater than 15 degrees Celsius below the alarm set point for twoseconds, or a high motor temperature alarm becomes active.

A no configuration warning is detected when the compressor model number,serial number and MCC current is not programmed into the memory. A noconfiguration warning is reset when the compressor model number, serialnumber AND MCC current is programmed into the memory. There is no checkfor accuracy of the text entered in for model and serial number and anynon-zero number for MCC value is valid.

A contactor life warning is detected when the number of compressorstarts equals 50,000 or a multiple of 50,000 (i.e., 100 k, 150 k, 200 k,etc.). A contactor life warning is reset when the system module ispowered off and on, indicating the contactor has been inspected and/orreplaced.

In general, the sensor system 66 detects compressor operating conditionssuch as the compressor faults listed above in Table 1 and the compressorwarning conditions, and provides a signal to the processing circuitry 68indicative thereof. The processing circuitry 68 is either amicrocontroller or a microprocessor such as microcontroller model numberPIC18F242, manufactured by Microchip Technology of Chandler, Ariz. Theprocessing circuitry 68 is in communication with the power interruptionsystem 70 and selectively actuates the power interruption system 70 inresponse to unfavorable conditions detected by the sensor system 66 suchas, but not limited to, the aforementioned “fault conditions.” Moreparticularly, the power interruption system 70 selectively restrictspower to the compressor motor 32 in response to direction from theprocessing circuitry 68 to prevent damage to the compressor 10 whensensed compressor operating conditions are outside of a predeterminedlimit.

With particular reference to FIGS. 3-6, the sensor system 66 is shown toinclude a scroll sensor 72, a motor temperature sensor 74, and a rotorsensor 76. The scroll sensor 72 is positioned generally proximate to theorbiting scroll member 40 and the non-orbiting scroll member 48 suchthat the temperature in an area surrounding the orbiting scroll member40 and non-orbiting scroll member 48 may be detected. The motortemperature sensor 74 is positioned generally proximate to the windings36 of the electric motor 32 and detects the temperature generallysurrounding the windings 36.

The rotor sensor 76 is positioned proximate to the rotor 38 of electricmotor 32 and senses when the rotor 38 is in a “locked rotor condition.”When the rotor 38 is restricted from moving relative to the windings 36,a force is applied between the windings 36 and rotor 38 as thecrankshaft 30 tries to rotate the windings 36. As can be appreciated,when the motor 32 attempts to rotate the crankshaft 30 and is restrictedfrom doing so due to the locked condition of the rotor 38 relative tothe windings 36, excessive current is drawn from an external powersource and the rotor 38 begins to experience an elevated temperature.The increase in current draw is monitored by the rotor sensor 76 so thatthe compressor 10 may be shut down if a predetermined current isdetected, as will be discussed further below.

With particular reference to FIG. 4, the sensor system 66 is shown tofurther include a cluster block 78 and a printed circuit board (PCB) 80.The cluster block 78 includes a housing 82, power apertures 84, andsensor apertures 86. The power apertures 84 are connected to threehigh-voltage leads 88 extending from the housing 82. The high-voltageleads 88 are operable to supply the electric motor 32 with power tothereby drive the crankshaft 30 and orbiting scroll member 40. Thehigh-voltage leads 88 extend from the housing 82 and terminate at thePCB 80, as best shown in FIG. 4.

The PCB 80 operably supports the motor temperature sensor 74 and rotorsensor 76 in close proximity to the electric motor 32. The motortemperature sensor 74 is disposed on a bottom surface of the PCB 80 andis held in close proximity to the windings 36 of the motor 32 such thatthe motor temperature sensor 74 is able to detect temperature changes inthe windings 36. The motor temperature sensor 74 is a thermistor able todetect temperature fluctuations in the windings 36 and may be configuredas either a NTC or a PTC device, depending on the particularapplication. If the motor temperature sensor 74 is configured as a NTCdevice, the signals coming from the motor temperature sensor 74 areconnected in parallel. If the motor temperature sensor 74 is configuredas a PTC device, then the sensed signals coming from the motortemperature sensor 74 are connected in series.

The rotor sensor 76 is generally disposed on an opposite side of the PCB80 from the motor temperature sensor 74, as best shown in FIG. 4. Therotor sensor 76 generally includes a sensor pin 90 electricallyconnected to a terminal end of each high-voltage lead 88. The sensorpins 90 are specially designed current carrying elements and areoperable to localize an inherent electrical resistance of each pin at aspecific point along its geometry indicative of the current flowingthrough each pin 90. As can be appreciated, the current flowing througheach sensor pin 90 is dictated by the amount of power drawn by theelectric motor 32. When the rotor 38 is in a locked condition, the motor32 begins to draw more current through each pin 90, thereby increasingthe temperature of each pin 90 at the localized point, as will bedescribed further below.

In addition to the sensor pins 90, the rotor sensor 76 further includesa temperature sensor 92 disposed proximate to each sensor pin 90, asbest shown in FIG. 4. The temperature sensors 92 detect a change intemperature along the length of the sensor pin 90, and may be configuredas either an NTC or a PTC thermistor. Generally speaking, eachtemperature sensor 92 is positioned along the length of each sensor pin90 such that it is proximate to the localized spot of increasedelectrical resistance so as to best detect a temperature change alongthe length of each individual pin 90. As can be appreciated, when morecurrent is drawn through each sensor pin 90 by the electric motor 32,each pin 90 will experience electric resistance at the localized point,as previously discussed. By placing each temperature sensor 92 proximateto the localized point of resistance along each sensor pin 90,fluctuations in temperature caused by increased current draw througheach sensor pin 90 will be quickly and accurately detected and may befed back to the processing circuitry 68, as will be discussed furtherbelow.

In addition to supporting the motor temperature sensor 74 and rotorsensor 76, the PCT 80 is also operably connected to the scroll sensor72, as best shown in FIG. 4. The scroll sensor 72 is a temperaturesensor and is operable to detect temperature fluctuations proximate to,or caused by, the orbiting scroll member 40 and non-orbiting scrollmember 48. The scroll sensor 72 is a thermistor and may be configured asan NTC thermistor or a PTC thermistor, depending on the particularapplication.

The PCB 80 serves as a termination point for the scroll sensor 72, motortemperature sensor 74, sensor pins 90, and temperature sensors 92.Specifically, the scroll sensor 72 is operably connected to the PCB 80via low-voltage leads 94, while the motor temperature sensor 74 andtemperature sensors 92 are directly connected and supported by the PCB80, as best shown in FIG. 4. As previously discussed, each of the scrollsensor 72, motor temperature sensor 74, and rotor sensor 76 are operableto detect respective temperature fluctuations within the shell 14 of thecompressor 10. Because each of the scroll sensor 72, motor temperaturesensor 74, and rotor sensor 76 terminate at the PCB 80, the PCB 80serves as a relay to transmit the sensed signals from each of therespective sensors 72, 74, 76, through the shell 14 of the compressor 10to the processing circuitry 68 and power interruption system 70.

A low-voltage lead 96 extends from the PCB 80 to the cluster block 78and is connected to the sensor apertures 86. As can be appreciated, thenumber of low-voltage leads 96 extending from the PCB 80 to the clusterblock 78 will depend on the number of sensors disposed within theinterior volume 22 of the compressor 10. In other words, the number oflow-voltage leads extending from the PCB 80 to the cluster block 78 willgenerally equal the number of sensors 72, 74, 92 disposed within thecompressor 10. However, each of the signals from the respective sensors72, 74, 92 may be combined and sent from the PCB 80 to the cluster block78 for transmission to the processing circuitry 68 and 70, therebyrequiring a single lead extending between the PCB 80 and the clusterblock 78. As can be appreciated, by combining the signals from therespective sensors 72, 74, 92, a reduction in the number of leads 96extending from the PCB 80 to the cluster block 78 may be reduced.

As previously discussed, the sensor assembly 66 is in communication withthe processing circuitry 68. To maintain a hermetic seal within thevolume 22 of the compressor 10, a hermetic terminal assembly 98 isprovided to establish an electrical connection between the sensorassembly 66 and processing circuitry 68, as best shown in FIG. 3.

The hermetic terminal assembly 98 includes a housing 100, a plurality ofhigh-voltage pins 102, a plurality of low-voltage pins 104, and ahermetic sealing material 106 surrounding the high and low-voltage pins102, 104. The housing 100 is fixedly attached to the shell 14 of thecompressor 10 by a suitable means such as welding or braising. Thehigh-voltage and low-voltage pins 102, 104 extend through the housing100 such that the high-voltage and low-voltage pins 102, 104 extend fromthe interior volume 22 to an exterior surface of the compressor 10, asbest shown in FIG. 3. The high-voltage and low-voltage pins 102, 104 aresurrounded by the hermetic sealing material 106 such that a hermeticseal is formed from an exterior surface of each pin 102, 104 and thehousing 100. In this manner, the terminal assembly 98 effectively allowscommunication between the sensor assembly 66 and processing circuitry 68while maintaining the hermetic seal of the compressor 10.

The processing circuitry 68 is disposed on an outer surface of thecompressor 10 and is in communication with both the terminal assembly 98and the sensor assembly 66. Specifically, the processing circuitry 68 ishoused generally within the electrical enclosure 28 and may beincorporated into a suitable plug 108 for interaction with the hermeticterminal assembly 98. Upon assembly, the plug 108 receives each of thehigh-voltage and low-voltage pins 102, 104 such that an electricalconnection is made between the processing circuitry 68 and hermeticterminal assembly 98. In addition, the high-voltage and low-voltage pins102, 104 are received into the power apertures 84 and sensor apertures86, respectively, of the cluster block 78. In this manner, an electricalconnection is made between the processing circuitry 68 and sensorassembly 66 via the hermetic terminal assembly 98 and plug 108. While aplug 108 has been described, it should be understood that any suitableconnector may be used for transmitting a signal from within thecompressor 10 to the processing circuitry 68.

In addition to being electrically connected to both the hermeticterminal assembly 98 and sensor assembly 66, the processing circuitry 68is further connected to the power interruption system 70. The powerinterruption system 70 is disposed on an external surface of thecompressor 10 and is operable to selectively permit or restrict power tothe electric motor 32. As can be appreciated, when the sensors 72, 74,92 indicate that conditions are unfavorable within the compressor 10,the processing circuitry 68 will direct the power interruption system 70to restrict power from reaching the electric motor 32, therebyeffectively shutting down the compressor 10. In this manner, the sensorassembly 66, processing circuitry 68, and power interruption system 70are operable to shut down the compressor 10 via restricting power to theelectric motor 32 when conditions in the compressor 10, or within asystem the compressor 10 may be tied to, are unfavorable for furtheroperation.

In addition to the above, the processing circuitry 68 also stores theconfiguration parameters of the compressor 10. Specifically, thecompressor model, compressor serial number, motor sensor type, MCClevel, discharge temperature, motor temperature, current transformercalibration offset, slave addressing, and device name are all storedwithin the processing circuitry 68. Of the above parameters, only thecompressor model, serial number, slave addressing, and device name arefield configurable.

With particular reference to FIGS. 5 and 6, the operation of thecompressor 10 and associated compressor protection and control system 12will be described in detail. As previously discussed, the powerinterruption system 70 regulates power directed to the electric motor 32of the compressor 10 by selectively engaging a contact 110 disposedexternal from the compressor 10 to thereby selectively restrict andpermit power to the electric motor 32.

In operation, the processor 68 monitors the combined signal of both themotor temperature sensor 74 and scroll temperature sensor 72 andselectively shuts down the compressor 10 in response to detected systemparameters. Specifically, if the actual value of the temperaturedetected by either the motor temperature sensor 74 or scroll temperaturesensor 72 exceeds a preprogrammed limit such that a fault condition isdetected, the processing circuitry 68 directs the power interruptionsystem 70 to disconnect the contact 110, thereby restricting power fromreaching the electric motor 32. In addition, the processing circuitry 68further creates a fault signal and directs such signal to a diagnosticoutput 112 for recording. As can be appreciated, registered faultswithin the compressor 10 may be valuable diagnostic tools in trackingand preventing further faults and failures within the compressor 10. Bysending fault signals to the diagnostic output 112, the processingcircuitry 68 effectively registers each time the compressor 10 is shutdown and maintains a record of each fault condition experienced.

As previously discussed, the rotor sensor 76 detects when the rotor 38is locked relative to the windings 36. When the rotor 38 is in a “lockedrotor condition” the electric motor 32 still draws current through thesensor pins 90 in an effort to rotate the crankshaft 30 and rotor 38relative to the windings 36. In so doing, the electric motor 32 draws asignificant amount of current through each sensor pin 90 to overcome thelocked condition between the rotor 38 and windings 36, therebyincreasing the temperature of each sensor pin 90. When the sensor pins90 realize an increase in temperature, the temperature sensors 92 relaya signal indicative of the temperature increase back to the processingcircuitry 68.

When the temperature sensors 92 indicate an increase in temperature ateach pin 90, the processing circuitry 68 correlates the sensedtemperature to a current flowing through each pin 90. In this manner,the temperature sensors 92 cooperate with the processing circuitry 68 toeffectively function as a current sensor to monitor the current througheach pin 90 and detect a locked rotor condition. When a thresholdcurrent has been established through the pins 90, the processingcircuitry 68 is operable to direct the power interruption system 70 torestrict power to the motor 32 and shut down the compressor 10.

In addition to sending a signal to the power interruption system 70, theprocessing circuitry 68 also sends a diagnostic signal to the diagnosticoutput 112 to record the “locked rotor” fault experienced within thecompressor 10. By storing and tracking faults, the compressor protectionand control system 12 effectively allows a user to monitor and trackproblems experienced by the compressor 10 in an effort to prevent anddetect problems in the future, as previously discussed.

Compressor protection and control system 12 has thus far been describedas having three temperature sensors 92, each disposed proximate to thesensor pins 90. FIG. 5 schematically represents an input to theprocessing circuitry 68 from each one of the temperature sensors 92. Itshould be understood, however, that the three temperature sensors 92could be fed into one signal, whereby the lone signal is sent to theprocessing circuitry 68 via hermetic terminal assembly 98, as best shownin FIG. 6. In such a relationship, the system 12 is simplified byreducing the number of signals coming from the individual temperaturesensors 92. In addition to the aforementioned sensors 72, 74, 76, itshould be understood that other sensors could be used within thecompressor 10 and should be considered as part of the present invention.Specifically, it is anticipated that an oil level sensor or oiltemperature sensor, generically referred to in FIG. 6 as 114, could alsobe incorporated into the compressor protection and control system 12 foruse in tracking diagnostics within the compressor 10, and should beconsidered with in the scope of the present invention.

With particular reference to FIGS. 7-11, a second embodiment of thecompressor protection and control system 12 will be described in detail.In view of the substantial similarity in structure and function of thecomponents associated with the compressor protection and control system12 and the compressor protection and control system 12 a, like referencenumerals are used here and in the drawings to identify like components.

The compressor protection and control system 12 a functions in a similarfashion to that of the compressor protection and control system 12, withrespect to the scroll sensor 72 and motor temperature sensor 74. In thismanner, detailed descriptions of the scroll sensor 72 and motortemperature sensor 74 are foregone.

The rotor sensor 76 a is disposed within the electric box 28 andgenerally includes a sensor pin 90 electrically connected to ahigh-voltage lead 88. The sensor pins 90 are a specially designedcurrent carrying elements and localize an inherent electrical resistanceof each pin at a specific point along its geometry indicative of thecurrent flowing through each pin 90. As can be appreciated, the currentflowing through each sensor pin 90 is dictated by the amount of powerdrawn by the electric motor 32. When the rotor 38 is in a lockedcondition, the motor 32 begins to draw more current through each pin 90,thereby increasing the temperature of each pin 90 at the localizedpoint, as will be described further below.

In addition to the sensor pins 90, the rotor sensor 76 a furtherincludes a temperature sensor 92 disposed proximate to each sensor pin90. The temperature sensors 92 are operable to detect a change intemperature along the length of the sensor pin 90, and may be configuredas either an NTC or a PTC thermistor. Generally speaking, eachtemperature sensor 92 is positioned along the length of each sensor pin90 such that it is proximate to the localized spot of increasedelectrical resistance so as to best detect a temperature change alongthe length of each individual pin 90. As can be appreciated, when morecurrent is drawn through each sensor pin 90 by the electric motor 32,each pin 90 experiences electric resistance at the localized point. Byplacing each temperature sensor 92 proximate to the localized point ofresistance along each sensor pin 90, fluctuations in temperature causedby increased current draw through each sensor pin 90 will be quickly andaccurately detected and may be fed back to the processing circuitry 68.

The rotor sensor 76 a allows the processing circuitry 68 to more quicklyrespond to an increase in current draw by the motor 32 and thereforeincreases the ability of the compressor protection and control system 12a to protect the compressor 10. More particularly, because the rotorsensor 76 a is disposed external from the interior space 22 of thecompressor, the power drawn by the motor 32 may be monitored prior toactually entering the compressor shell 14. Monitoring the current drawupstream from the motor 32 allows for a quicker response time as theprocessing circuitry 68 is not required to wait for the current totravel along the high-voltage leads 88 and through the hermeticinterface 98 prior to taking a reading. The improved response timeallows the processing circuitry 68 to more quickly direct the powerinterruption system 70 to restrict power to the motor 32, and thus,reduces the probability of compressor damage.

With particular reference to FIGS. 12-18, a third embodiment of thecompressor protection and control system 12 will be described in detail.In view of the substantial similarity in structure and function of thecomponents associated with the compressor protection and control system12 and the compressor protection and control system 12 b, like referencenumerals are used here and in the drawings to identify like components.

The compressor protection and control system 12 b functions in a similarfashion to that of the compressor protection and control system 12, withrespect to the scroll sensor 72 and motor temperature sensor 74. In thismanner, detailed descriptions of the scroll sensor 72 and motortemperature sensor 74 are foregone.

The rotor sensor 76 b is disposed within the electrical enclosure 28 bsuch that the rotor sensor 76 b is removed from the interior space 22 ofthe compressor 10. The rotor sensor 76 b includes a cluster block 116that matingly engages the hermetic terminal assembly 98 and a currentsensor 118 that detects a current drawn by the electric motor 32.

The cluster block 116 includes a pair of arms 120 flanking a centralbody 122, as best shown in FIG. 13. Each of the arms 120 and centralbody 122 includes a high-voltage lead 88 extending therefrom. Inaddition, the main body 122 includes a pair of low-voltage leads 96extending therefrom for receiving and transmitting signals from thesensor assembly 66 b, as will be described further below. As best shownin FIG. 13, the cluster block 116 matingly engages the hermetic terminalassembly 98 such that each of the high-voltage leads 98 engage thehigh-voltage pins 102 and the low-voltage leads 96 engage thelow-voltage pins 104. In this manner, the cluster block 116 effectivelyconnects the high-voltage power leads 88 and low-voltage sensor leads 96to the sensor system 66 a and motor 32 disposed within the compressor10.

The current sensor 118 is disposed proximate to the cluster block 116,as best shown in FIG. 14. The current sensor 76 b includes a series ofindividual sensing elements 124, each having a high-voltage lead 88extending therethrough. The sensor elements 124 detect a current flowingthrough each of the high-voltage leads 88 and produce a signalindicative thereof. The signal produced by the sensing elements 124 issent to the processing circuitry 68 b to compare the sensed current to athreshold limit and determine whether the electric motor 32 is in a“locked rotor state” or another fault condition.

If the processing circuitry 68 b determines that the current flowingthrough the high-voltage leads 88 exceeds the threshold limit, theprocessing circuitry 68 b will send a signal to the power interruptionsystem 70 to restrict power to the electric motor 32 and shut down thecompressor 10.

As previously discussed, the processing circuitry 68 b sends a signal tothe power interruption system 70 to restrict power to the electric motor32 should an undesirable condition be experienced within the compressor10. In addition, the processing circuitry 68 b also alerts an operatorthat a system fault has occurred within the compressor 10 byilluminating a series of light-emitting devices (LED) 126, as will bediscussed further below.

With particular reference to FIGS. 14-18, the operation of thecompressor 10 and associated compressor protection and control system 12b will be described in detail. As previously discussed, the scrollsensor 72, motor temperature sensor 74, and rotor sensor 76 b detectoperating conditions and parameters of the compressor 10. The sensedsignals from the individual sensors 72, 74, 76 b are sent to theprocessing circuitry 68 b for comparison to a set of predeterminedcompressor operating parameters. Should the processing circuitry 68 bdetermine that the sensed parameters from the individual sensors 72, 74,76 b exceed the predetermined compressor operating parameters, theprocessing circuitry 68 b will alert the power interruption system 70 torestrict power to the electric motor 32 to thereby shut down thecompressor 10.

When the compressor 10 is initially started, the system is in a readymode, as indicated in FIG. 17. At this point, the processing circuitry68 b checks for any fault conditions. If a fault condition is detected,the processing circuitry 68 b bypasses the run mode of the compressor 10and causes the compressor 10 to enter a shutdown mode. In the shutdownmode, the compressor 10 attempts to recover the system without fullyshutting down power to the electric motor 32, depending on theparticular fault condition experienced. However, if the fault conditionexperienced is a significant fault, the shutdown mode enters a lockoutor a no control phase, whereby the compressor 10 will need to be shutdown completely such that power is restricted from reaching the electricmotor 32. In such a condition, the compressor 10 is not be able to enterthe run mode until the processing circuitry 68 b directs the powerinterruption system 70 to restrict power to the electric motor 32.Restarting the compressor 10 by restricting power often clears the faultand allows the compressor 10 to properly operate.

When the compressor 10 is returned to the ready mode, or when thecompressor 10 is initially started from startup and no fault conditionsare detected, the compressor 10 enters the run mode, as indicated inFIGS. 17 and 18. The compressor 10 continues to run and the processingcircuitry 68 b will cause the diagnostic 112 to continually record eachsuccessful run. Once ten successful runs have been achieved, theprocessing circuitry 68 b clears the fault memory and restarts thesystem anew. In this manner, the processing circuitry 68 b receivessensed system parameters from the individual sensors 72, 74, 76 b andselectively shuts down the compressor 10 when system conditions warrant.In addition, the processing circuitry 68 b also collects data during anoperational mode of the compressor 10 via diagnostic 112 to therebystore and track faults. As can be appreciated, by storing and trackingsuch faults, the processing circuitry 68 b is able to detect and preventpossible future failures and faults by the compressor 10.

When the compressor 10 is in the run mode, the LED 126 illuminates agreen light to indicate that the compressor 10 is running under normalconditions, as best shown in FIG. 18. In addition, a second LED 126 mayalso be illuminated to indicate that the contactor 110 is supplyingpower to the electric motor 32. In the event that a fault is detected, ayellow LED 126 is illuminated to indicate that the compressor 10 hasexperienced a fault and is in need of attention. If the processingcircuitry 68 b determines that the fault condition is a significantfault, such that the compressor 10 will not be able to recover withoutshutting down, the processing circuitry 68 b directs the powerinterruption system 70 to restrict power the compressor 10, aspreviously discussed.

When the power interruption system 70 shuts down the compressor 10, ared LED 126 is illuminated to alert an operator that the compressor 10has been shut down due to a fault condition. At this point, the green“run” and “contactor” LEDs 126 is turned off to indicate that thecompressor 10 is no longer running under normal conditions, and that thecontactor 110 has been disengaged from the power supply. It should benoted that at this point, the only LED 126 illuminated is the red alarm,indicating that the compressor 10 has been shut down and has logged afault. As can be appreciated, by using such LEDs 126, the compressorprotection and control system 12 b allows the compressor 10 to indicatewhen a fault condition has been experienced so that proper actions canbe taken, as best shown in FIG. 18.

Generally speaking, the LED alarms are divided into supply power alarmsand compressor alarms. The respective supply power and compressor alarmsare communicated to the user by denoting a specific alarm with adesignated number of LED flashes. Specifically, the supply power alarmsinclude run winding delay (one flash), missing phase (two flashes),reverse phase (three flashes), welded contactor (four flashes), lowvoltage (five flashes), and no three phase power (six flashes). Thecompressor alarms include low oil pressure (one flash), dischargetemperature (two flashes), motor temperature (three flashes), lockedrotor (four flashes), motor overload (five flashes), and open thermistor(six flashes). Therefore, the user can easily determine the respectivefault condition by simply referring to the respective LED 126.

With particular reference to FIGS. 19-20, a fourth embodiment of thecompressor protection and control system 12 will be described in detail.In view of the substantial similarity in structure and function of thecomponents associated with the compressor protection and control system12 and the compressor protection and control system 12 c, like referencenumerals are used here and in the drawings to identify like components.

With reference to FIG. 19, the plural compressor 10 c is shown toinclude a generally cylindrical hermetic shell 14 c having a pair ofwelded caps 16 c, 18 c and a plurality of feet 20 c. The caps 16 c, 18 care fitted to the shell 14 c such that an interior volume 22 c of thecompressor 10 c is defined. In addition, an electrical enclosure 28 c isfixedly attached to the shell 14 c generally between the caps 16 c, 18 cand operably supports a portion of the protection system 12 c therein,as will be discussed further below.

A crankshaft 30 c is rotatively driven by an electric motor 32 crelative to the shell 14 c. The motor 32 c includes a stator 34 cfixedly supported by the hermetic shell 14 c, windings 36 c passingtherethrough, and a rotor 38 c press fitted on the crankshaft 30 c. Themotor 32 c and associated stator 34 c, windings 36 c, and rotor 38 c areoperable to drive the crankshaft 30 c relative to the shell 14 c tothereby compress a fluid.

The plural compressor 10 c further includes a pair of orbiting scrollmembers 40 c, each having a spiral vane or wrap 42 c on the uppersurface thereof for use in receiving and compressing a fluid. An Oldhamcoupling 44 c is positioned between orbiting scroll members 40 c and abearing housing 46 c and is keyed to orbiting scroll members 40 c and apair of non-orbiting scroll members 48 c. The Oldham coupling 44 c isoperable to transmit rotational forces from the crankshaft 30 c to theorbiting scroll members 40 c to thereby compress a fluid disposedbetween the orbiting scroll members 40 c and non-orbiting scroll members48 c. Oldham coupling 44 c and its interaction with orbiting scrollmembers 40 c and non-orbiting scroll members 48 c is preferably of thetype disclosed in assignee's commonly-owned U.S. Pat. No. 5,320,506, thedisclosure of which is incorporated herein by reference.

Non-orbiting scroll members 48 c also include a wrap 50 c positioned inmeshing engagement with wrap 42 c of orbiting scroll members 40 c.Non-orbiting scroll members 48 c have a centrally disposed dischargepassage 52 c which communicates with an upwardly open recess 54 c.Recesses 54 c serve to store compressed fluid are disposed at oppositeends of the interior volume 22 c such that a first recess 54 c ispositioned proximate cap 16 c and a second recess 54 c is positionedproximate cap 18 c.

Plural compressor 10 c is preferably of the type disclosed in assignee'scommonly-owned U.S. Pat. No. 6,672,846 and U.S. patent application Ser.No. 10/600,106 filed on Jun. 20, 2003, published as U.S. 2004-0258542A1,the disclosures of which are incorporated herein by reference.

The compressor protection and control system 12 c functions in a similarfashion to that of the compressor protection and control system 12 b,with respect to the scroll sensor 72 and motor temperature sensor 74. Inthis manner, detailed descriptions of the scroll sensor 72 and motortemperature sensor 74 are foregone.

The rotor sensor 76 c is disposed generally within electrical box 28 csuch that current to the motor 32 c is sensed prior to entering theshell 14 c. The rotor sensor 76 c is substantially identical to sensor76 b, but requires three additional sensing elements 124 to handle anadditional current draw by the motor 32 c. Specifically, because theplural compressor 10 c drives a pair of orbiting scroll members 40 crelative to a pair of non-orbiting scroll members 48 c, a larger motor32 c is required and, thus, more current is drawn. The increased powerrequirement causes additional high-voltage lines 88 to extend betweenthe hermetic terminal assembly 98 and motor 32 c. In this manner, therotor sensor 76 c requires a total of six sensing elements 124 toaccommodate the additional high-voltage leads 88.

FIGS. 21 and 22 show a perspective view of the processing circuitry 68 cand rotor sensor 76 c. Six sensing elements 124 are shown proximate tohigh-voltage leads 88, such that the current drawn by the motor 32 c ismonitored. In addition, a plurality of sensor inputs are shown such asoil level inputs 134, motor temperature sensor inputs 136, dischargetemperature inputs 138, 140, alarm relays 140, power inputs 142, andcontactor inputs 144. In addition, a communication port 112 c is shownfor communication with an external network, as will be discussed furtherbelow. As can be appreciated, the inputs may be varied depending on theparticular application and will be largely dependent upon the sensorsystem 66 c disposed within the compressor 10 c. For example, ascroll-temperature input 146 could be added if a scroll sensor 72 isused within the compressor 10 c, as best shown in FIG. 21.

With particular reference to FIG. 23, the compressor 10 and associatedcompressor protection and control system 12 are shown incorporated intoa network 128. While the network 128 will be described with reference tocompressor 10 and compressor protection and control system 12 b, itshould be understood that compressor 10 c and other protection andcontrol systems 12, 12 a, 12 c could similarly be used in such anetwork. The network 128 includes a system controller 138 and aplurality of compressors 10. Each compressor 10 is in communication witha system controller 130 via a communications port 132. Thecommunications port 132 may be linked to the diagnostic 112 such thatfaults recorded by the processing circuitry 68 b logged in thediagnostic 112 may be supplied to the communication port 132 and systemcontroller 130. By doing so, the faults experienced by each individualcompressor 10 may be recorded and logged so that the proper maintenancemay be performed on each compressor 10. While the compressor protectionand control system 12 b has been described incorporated into the network128, it should be understood that the compressor protection and controlsystem 12 could similarly be implemented into such a network, and assuch, should be considered within the scope of the present invention.

As described, the compressor protection and control system 12 andcompressor protection and control system 12 b provide the compressor 10with the ability to detect and sense system parameters, to alertpotential faults through the use of LEDs 126, and to store faults viadiagnostic 112. In addition, in the case of the locked rotor condition,each of the current sensors 76, 76 b provide the system with the abilityto detect current draw by the motor 32, rather than relying solely onsensed motor temperatures. As can be appreciated, by sensing currentdraw, rather than waiting for a temperature signal to be produced andanalyzed, the systems 12, 12 a, 12 b, 12 c provide a quicker responsetime and thereby increase the productivity and performance of thecompressor 10.

The description is merely exemplary in nature and, thus, variations areintended to be within the scope of the teachings and not as a departurefrom the spirit and scope of the teachings.

1. A compressor assembly comprising: a shell; a compressor housed withinsaid shell; a motor drivingly connected to said compressor; a sensorassembly operable to monitor operating conditions of said compressor,said sensor assembly including at least one sensor sensing thetemperature of an electrical conductor supplying current to said motor.2. The compressor assembly of claim 1, wherein said at least one sensoris a negative temperature coefficient sensor.
 3. The compressor assemblyof claim 1, wherein said at least one sensor is disposed within saidshell.
 4. The compressor assembly of claim 1, wherein said at least onesensor is disposed external to said shell.
 5. The compressor assembly ofclaim 1, wherein said sensor assembly includes a printed circuit boarddisposed within said shell and operably supporting said at least onesensor.
 6. The compressor assembly of claim 5, wherein said printedcircuit board supports said electrical conductor.
 7. The compressorassembly of claim 1, wherein said electrical conductor includes a pinconnected to said motor to supply said motor with current.
 8. Thecompressor assembly of claim 7, wherein said pin is disposed within saidshell.
 9. The compressor assembly of claim 7, wherein said pin isdisposed external to said shell.
 10. The compressor assembly of claim 7,wherein said pin includes a measurement region disposed along said pinand said at least one sensor is disposed proximate to said measurementregion.
 11. The compressor assembly of claim 10, wherein saidmeasurement region includes a smaller cross-sectional area than theremainder of said pin.
 12. The compressor assembly of claim 1, furtherincluding processing circuitry operable to receive information from saidat least one sensor to determine an operating condition of saidcompressor.
 13. The compressor assembly of claim 12, wherein saidprocessing circuitry further comprises a series of light emittingdevices operable to selectively illuminate in response to sensedcompressor parameters.
 14. The compressor assembly of claim 12, whereinsaid processing circuitry includes a microprocessor.
 15. The compressorassembly of claim 1, wherein said sensor assembly further includes amotor temperature sensor operable to monitor a temperature of saidmotor.
 16. The compressor assembly of claim 1, wherein said sensorassembly further includes a compressor temperature sensor operable tomonitor a temperature of said compressor.
 17. The compressor assembly ofclaim 1, further comprising a hermetic feed-through assembly operable toconnect said sensor assembly to said processing circuitry through saidshell to maintain a hermetic seal of said compressor.
 18. The compressorassembly of claim 1, wherein said electrical conductor is seriallyconnected to said motor.
 19. The compressor assembly of claim 18,wherein said electrical conductor is serially connected to windings ofsaid motor.
 20. The compressor assembly of claim 18, wherein said motoris drivingly connected to said compressor and said sensor assembly isoperable to detect locked rotor conditions by monitoring the temperatureof said electrical conductor.
 21. A compressor assembly comprising: ashell; a compressor housed within said shell; a motor drivinglyconnected to said compressor; at least one current sensor operable tosense a current drawn by said motor; at least one temperature sensordisposed within said shell; and processing circuitry operable to receivedata from said at least one current sensor and said at least onetemperature sensor to determine operating conditions of said compressor.22. The compressor assembly of claim 21, wherein said at least onetemperature sensor is disposed proximate to a discharge port of saidcompressor and is operable to detect a discharge gas temperature. 23.The compressor assembly of claim 21, wherein said at least onetemperature sensor is disposed proximate to a discharge port of saidcompressor and is operable to detect a material temperature near saiddischarge port.
 24. The compressor assembly of claim 21, wherein said atleast one temperature sensor is a negative temperature coefficientsensor.
 25. The compressor assembly of claim 21, further comprising aprinted circuit board disposed within said shell.
 26. The compressorassembly of claim 25, wherein said printed circuit board operablysupports said at least one temperature sensor.
 27. The compressorassembly of claim 21, wherein said current sensor is disposed withinsaid shell.
 28. The compressor assembly of claim 21, wherein saidcurrent sensor is disposed external from said shell.
 29. The compressorassembly of claim 21, wherein said at least one temperature sensorincludes a motor temperature sensor operable to monitor a temperature ofsaid motor.
 30. The compressor assembly of claim 21, wherein said atleast one temperature sensor includes a compressor temperature sensoroperable to monitor a temperature of said compressor.
 31. The compressorassembly of claim 21, further comprising a hermetic feed-throughassembly operable to connect said at least one temperature sensor tosaid processing circuitry through said shell to maintain a hermetic sealof said compressor.
 32. The compressor assembly of claim 21, whereinsaid processing circuitry further comprises a series of light emittingdevices operable to selectively illuminate in response to sensedcompressor parameters.
 33. The compressor assembly of claim 21, whereinsaid processing circuitry includes a microprocessor.